Trilogy Settings with Progression

[katygal]

My PALS has been using a Trilogy for the past year. His latest FVC was 26%, with MIP at 20 and MEP at 32. We can tell his weakening muscles continue to affect his breathing, just since Clinic in February. He had some issues with air hunger at night and increasing EPAP from 6 to 8 took care of that issue. Lately, it seems he is experiencing more leakage with both masks and at times, he feels stronger or more air pressure, especially with the nasal only mask. Question: As the muscles continue to weaken, how does that "normally" affect the Trilogy settings for pressure and volume? We are very fortunate to have a DME company that works with lots of ALS patients using Trilogy machines but I wanted to have some understanding of how the settings may need to be changed has this progresses.

Thanks so much for any insight.

 

[lgelb]

Hi Katy,

I believe everyone should know how to change settings on the fly (it only takes a few seconds) and would be happy to help you learn how/why to do so. However good your RTs are, this is not a set and forget deal. Increasing the EPAP prevented his airway from collapsing when the pressure drops on exhale, but it will also make it more difficult for him to breathe against it over time, so you will likely end up playing with it some more, even day to day or hour to hour. When coughing or choking, that can be minute-to-minute (e.g. turning off the backup rate when coughing or choking).

As muscle tone continues to change, as well as breathing, masks may not fit as well, so you may need to add a liner esp. on the nose bridge/nostrils (which can be a commercial one or just a cut up T-shirt or some paper tape). As you say, you may also want to adjust the pressure depending on which mask he's wearing.

I'll PM you.

 

[KarenNWendyn]

Clearly the correct answer to this question is to titrate (adjust) settings as needed to achieve maximum comfort, and this will vary from PALS to PALS and change over time.

But I think what Katy is asking, and I also wonder, is that over the course of ALS as respiratory muscles weaken, what sort of trends can we generally expect for the following?

*Backup rate
*Minimum and maximum inspiratory pressures
*Minimum and maximum expiratory pressures
*Tidal volume

I agree all PALS/ CALS should be comfortable changing their own settings, but it is helpful to have a sense of the directions in which to change them as respiratory muscles weaken.

Hopefully Laurie and other experienced PALS and CALS who have been dealing with BiPAP for a long time can weigh in.

 

[katygal]

Yes, Karen asked by question better than I did. What trends are usually seen on the 4 settings she listed?

 

[lgelb]

Great questions, Karen, but unfortunately I can't specify a direction. That's why I have to ask all the questions on emails that some of you have had occasion to read (and are also summarized on my profile).

Some PALS go up, others go down, on each set of parameters that you mentioned. Some go up on some and down on some. There are several reasons for this:

Some lose lung capacity so volume needs to go down if only to avoid pneumothorax not to mention discomfort. Others' air hunger is only satisfied with higher volumes, that they are able to handle.

Some have EPAP set too high to begin with or had it set higher for obstructive apnea that tends to drop out late in life, and need to go down so they are breathing against minimum pressure. Others such as Katygal's PALS need to go up on EPAP to keep the airway open.

Some need more pressure support (PS -- difference between IPAP and EPAP at any given time) to force air into the lungs whereas others are more comfortable [and sometimes even better off from an O2 and/or CO2 standpoint) breathing more shallowly as ALS progresses.

Desirable number of breaths per minute/duration of/time between breaths are other values that can go either way, that we can set the machine to support and get less "wrong" rather than force.

The last of the issues I'll mention is that my recommendations for settings can vary depending on the PALS' view of things overall -- whether s/he feels s/he is near the end of life and willing to trade off CO2 retention and/or low sats that could hasten death for greater comfort, or is still looking to extend life. That is one reason that I recommend CALS know how to change settings, since someone who changes categories may do so over time or the situation may turn on a dime.

Best,
Laurie